Messages

481

General Discussion / Regulator board & ARF Board

« on: August 31, 2015, 05:50:03 pm »

I've been asked by a friend to make him up a PilotAware unit.  Reading through the document for these two items I have been mulling over creating a custom shield with a 3.3v regulator to take the ARF board, which then just gets plugged directly onto the GPIO block on the Pi.  This would save the making up of IDC cables and gluing various parts to cases etc.

Would anyone else be interested in such a board? 

482

General Discussion / Re: Power Supply & USB Power Cable

« on: August 30, 2015, 10:00:28 pm »

How about a Charge 4 USB Power?

 http://www.charge4.co.uk/

They are Software run. I currently use on on the IPad. But not yet tested with Pilotaware.

Richard.

Just a report back on using the charge2 for powering everything..... It appears I needed an upgrade for the unit I was using. "J" has very kindly exchanged the unit for an updated charge2 unit. All works very well with no power drops at all it powers the iPad and the PilotAware with no problems. Also no rf noise on the radio or headset. A perfect combination.

Richard

Glad it's all sorted 

483

General Discussion / Re: Power Supply & USB Power Cable

« on: August 16, 2015, 09:16:23 pm »

Lee,

Any reason for the B+ over the more recent Pi 2, I thought they shared the same physical layout?

There is an issue to be resolved with the driver for the dvbt dongle
Thx
Lee

OK, Thanks.  I'll look at ordering some parts over the next couple of days.

484

General Discussion / Re: Power Supply & USB Power Cable

« on: August 16, 2015, 06:24:27 pm »

Lee,

Any reason for the B+ over the more recent Pi 2, I thought they shared the same physical layout?

485

General Discussion / Re: Power Supply & USB Power Cable

« on: August 16, 2015, 05:55:31 pm »

OK Lee,
    I Have tested PilotAware and the Charge2 today in the air from Sherburn (Very Busy in the air today) I could not get the Charge2 to operate correctly with the PilotAware, The Charge2 tries to keep connecting power to the PilotAware but keeps turning the power off and re-starting again. It does this some times when I plug in the Ipad. I'm not sure why? It needs JCurtis to clarify what may be happening. It is as thought the Charge2 keeps re-starting, (Red light flashing, No green lights) Ipad only Works fine.

Richard,

Can I ask a few questions...

Did you order your Charge2 around the end of March (just so I can track the order)
Do you have the Charge2 powered when you start the aircraft?
Does the problem appear with Charge2 running but the engine not started?
Do you sometimes have issues with the iPad only too?
When you see the issue does the iPad beep to say it has power, you see a green light on the Charge2, it flash red light and the cycle repeats?

If you prefer, and to save cluttering this thread, you can reply direct to charge4@harkwood.co.uk

A friend has asked me to make him up one of the PilotAware units, so over the next couple of weeks I will be able to test this here.  I have the previous generation of Pi and the newer one may behave differently.

486

General Discussion / Re: Power Supply & USB Power Cable

« on: August 15, 2015, 10:57:10 am »

Can you post a link to your reference ?
Thx
Lee

The regulator is a common part, made by various companies, all the data sheets vary to a degree.  You can see in the pic the IC model code of AMS1117 3.3 which makes that item the AMS version (data sheet linked below, which is pretty thin).  TI also make the same part their data sheet is a little more in-depth.  As they are interchangeable parts for which they will probably fit who ever is cheapest at the time of manufacture, they should take into account the worst use case.  Both these data sheets state a 22uF for Cout, the TI also gives recommendations for Cin.

I doubt it will make a huge difference, but it would be interesting to scope the output just to be sure, especially given the application - you don't want surprises with the radio module playing up.

http://www.advanced-monolithic.com/pdf/ds1117.pdf
http://www.ti.com/lit/ds/symlink/lm1117-n.pdf

487

General Discussion / Re: Power Supply & USB Power Cable

« on: August 15, 2015, 08:34:44 am »

Are you referring to the 3.3v regulator on the pi itself ?

No not the one on the Pi but the additional ARF 3.3v regulator shield.  This is only going by the silkscreen but it looks like they have 1uF on the input and 10uF on the output.  The data sheet recommends 10uF and 22uF respectively. Might not be an issue but it would be interesting to see the output as the load jumps up and down.

488

General Discussion / Re: Power Supply & USB Power Cable

« on: August 14, 2015, 07:31:00 pm »

Hi,

I am the designer and maker of the Charge2 USB chargers mentioned in this post.  If anyone has any questions over them, please feel free to drop me an e-mail to the address on the website.

Have to say this looks like an interesting project.  I dug out the previous generation Pi I have here and powered it up via a Charge2, it all seemed to be working fine.

if you need any help getting accurate power readings etc. I have various tools and test gear which can help with that.

Hi Jeremy

Many thanks for the heads up on your findings.
I would just point out that by default, the Pi draws quite a small amount of current, probably about 600mA.
Could you clarify the figures I quoted would be OK, whereby I expect the Pi in this setup to be drawing a peak current, possibly upto 1.5A

In this configuration, the radio module pulses for about 1-5ms ever 1-2 seconds, which would result in a spike of current draw of 330mA, so in other words the effective quiescent current is probably about 750mA, with the cyclic pulse of an additional 330mA taking the total to approx 1.1A.

I think your unit could cope with that no problem, but wanted to give you the opportunity to comment.

Thx
Lee

The chargers have a very fast transient load response combined with reasonable capacitance on each output port.  I can look at simulating that kind of load by pulsing GPIO pins with loads on etc. but I don't think it would be a problem in terms of voltage or current.

As an aside, looking at the 3.3v regulator (based on the pic of it anyway) it seems it employs a AMS1117 LDO regulator, which the data sheet for recommends 22uF output capacitance but the silk screen says 10uF.  It would be interesting to scope the output of them with the radio is running to ensure it's stable.

489

General Discussion / Re: Power Supply & USB Power Cable

« on: August 14, 2015, 05:37:29 pm »

Hi,

I am the designer and maker of the Charge2 USB chargers mentioned in this post.  If anyone has any questions over them, please feel free to drop me an e-mail to the address on the website.

Have to say this looks like an interesting project.  I dug out the previous generation Pi I have here and powered it up via a Charge2, it all seemed to be working fine.

if you need any help getting accurate power readings etc. I have various tools and test gear which can help with that.